Supplementary bonding - connecting cable and CPC?

Question

I'm sorting out the supplementary bonding in my bathroom at the moment, and understand that I need to connect the 4mm bonding cable to the CPC of the shaver-light.

To be strictly kosher, how should that be achieved in practice? The shaver-light is wired from a junction box on the upstairs lighting circuit, but clearly the terminals aren't big enough to take the 4mm cable. I imagine that if I used a choc-box affair instead, with big enough terminals, these wouldn't grip the small 1mm wires of the lighting cable. Is it allowed to cut off a couple of strands of the bonding cable so it fits into the jcb terminal? That sounds decidedly dodgy to me - but if not, what's the correct way?

Thanks David

John Rumm · Accepted Answer

Using a JB intended for power rather than lighting circuits would give you the terminal space. If you use one of the MK ones with individual wire holes in each terminal, you ought to have no difficulty gripping the smaller CPC (you can always fold the end over to make a bigger target). Shaving strands off the bonding conductor is not good practice!

ARWadworth · Answer

Is there no space at the bathroom lightfitting or pull switch to take this 4mm cable to?Adam

Lobster · Answer

Thanks for the replies.Light fittings are 12V downlighters, whose transformers are wired (IIRC) to the same JCB I'm talking about (or a similar one).Thinking about it though... the light switch is an ordinary wall switch outside the bathroom door, mounted in a stud partition - there will be a redundant CPC inside the switch backbox, which would be a much more convenient location to run the 4mm cable to than all the way up to the ceiling (either the cable will have to run within the stud partition which will require a bit of "surgery").  So I could connect it to the CPC in the lightswitch with a single large-size terminal connector. Excellent.ThanksDavid

Supplementary bonding - connecting cable and CPC?

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